Interconnected burner pilots



Aug. 15, 1961 c. H. KING, JR., ET AL 2,995,896

INTERCONNECTED BURNER PILOTS Filed June 5. 1953 FIG. I

34 INVENTORS CHARLES H. KING, JR.

LOUIS S. BILLMAN ATTORNEYS United States Patent 2,995,896 INTERCONNECTED BURNER PILOTS Charles H. King, In, Manchester, and Louis S. Billman,

Portland, Conn., assignors, by mesne assignments, to

the United States of America as represented by the Secretary of the Navy Filed June 5, 1953, Ser. No. 359,976 2 Claims. (Cl. 6039.72)

This invention relates to combustion apparatus for a ram jet propulsion power unit and more particularly to an apparatus which will assure simultaneous ignition and maintenance of a stable flame front between flame spreaders in a ram jet propulsion power unit under a Wide range of operating conditions.

Present combustion apparatus for use in ram jet propulsion combustion chambers employ several flame spreaders in the combustion zone to obtain optimum flame propagation and greater efliciencies. However, the high speed of the air mass flowing through the combustion chamber is substantially higher than the speed of flame propagation in the fuel and air mixtures employed thereby causing the flame spreaders to act independently of each other which results in the flame flashing back and forth between the flame spreaders.

The present invention has as an object to provide a ram jet engine with a combustion chamber in which a sheltered zone is provided for initiation of combustion and maintenance of a stable flame front.

Another object of this invention is to provide a diffuser assembly which will assure satisfactory operation over a wide range of air mass flows by protecting the flame against ext-inguishrnent.

Another aspect of this invention is to provide a streamlined supporting conduit for transferring a combustible mixture and flame from one combustion zone to another with a minimum of air blockage, fiictional pressure drop and burner pressure loss.

A further aspect of this invention is the provision of a means for sheltering a portion of the combustion chamber from the incoming main air flow.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a side elevation, partially in section, of one form of ram jet engine embodying the present invention;

FIG. 2 is an enlarged sectional view of the combustion chamber taken along a line substantially corresponding to line 2-2 of FIG. 1;

FIG. 3 is a longitudinal sectional View of a portion of the combustion chamber taken along a line substantially corresponding to line 3-3 of FIG. 2;

FIG. 4 is a rear perspective view illustrating the diffuser assembly unit of FIG. 1; and

FIG. 5 is a longitudinal view, partially in section, of another form of jet engine embodying the present invention.

Referring to the drawings wherein like numerals designate like parts, there is illustrated in FIG. 1 a ram jet duct in which the forward portion provides a mixing chamber for fuel and ram air prior to combustion in an aft combustion chamber 11. The air inlet 12 of the duct 10 provides an inlet through which sufficient ram air for combustion is collected and the volume of the incoming mass is permitted to expand sufficiently to decelerate its speed prior to entering the combustion chamber 11 and thereby converting the kinetic energy to potential energy for the thermic cycle. Protruding through the periphery of the forward portion of the ram jet duct 10 leading from the ram jet supporting member 13 is the fuel line ice 14 through which any suitable fuel may be metered to combine in the desired proportions with the incoming air to form a combustible air fuel mixture for injection into the duct through the fuel injection nozzle 15. Fuel 16 from the fuel nozzle 15 will be interspersed with the incoming air and in passing downstream will partially impinge against the apex 17 and wall 18 of a hollow conical diverter 19 coaxially supported within the duct 10.

Mounted at the entrance to the combustion chamber 11 is an annular diifuser assembly 20 having a frustoconical ring 21 through which the combustion mixture flows. The diffuser assembly 20 is secured to the inner periphery of the ram jet duct 10 through the mounting ring 22 at a suitable position from the fuel injection nozzle 15 with the base 23 or large end of the conical ring 21 facing the upstream side of the duct 10 and the converging or small end 24 of the conical ring facing the downstream or the entrance to the combustion area. A plurality of regularly spaced hollow struts 25 project radially from the conical diverter 19 to interconnect the hollow chamber 26 of the diverter 19 to the outer face 27 of the diffuser assembly 20 at the desired location through the diifuser, and illustrated by the area 28 in FIG. 3. The hollow struts 25 provide conduit means for the passage of a combustible mixture and flame propagation between the surrounding area 23 of the diffuser cone within the combustion chamber and the inner hollow chamber 26 of the diverter 19.

As the combustible mixture enters the diffuser assembly 20 the mixture and the excess air is Stratified or concentrated substantially into zones designated in FIG. 3 as A, B, and C. The high velocity, substantially annular, ram air mass in zone B apparently creates a relative negative pressure within the sheltered zone A adjacent the diverter cone which will induce eddy currents in zone C and the reduced pressures in zones A and C will set up a flow between the two zones in the direction of the sheltered and stabilized flame zone A.

An air fuel mixture passing through the diffuser assembly 20 into zone B will become dispersed partly as by eddy currents which infiltrate into zone C whereupon the mixture will be ignited in the zone C by any convenient means, such, for example, as a spark plug 29, and the flame will "advance from the area 28 through the hollow struts 25 and then the flame will be propagated to within sheltered zone A. The sheltered zone A provides a suitable means for initiation of combustion as well as providing for the maintenance of a stable flame front under all conditions of air flow by the shielding effect of the hollow diverter 19. Transmitting flames from one flame spreader to another through the hollow struts Without such flashing back and forth so as to keep all of the flame spreaders in operation is now feasible by employing the present invention.

The embodiment shown in FIG. 5 illustrates a diffuser assembly wherein -a modified diverter 30 is adapted to incorporate the trailing edge 31 of an inner body 32 supported within a conventional ram jet duct 33. Fuel 34 is injected into the airstream from the periphery of the inner body at suitably located nozzles 35. The diffuser assembly performs the same functions as set forth in the first embodiment illustrated.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In combination with a ram jet engine, a combustion chamber comprising an annular duct for receiving ram air therethrough, means including a nozzle disposed mounted in the duct downstream from said fuel supply means and having the converging wall throughout the length thereof in spaced relation with respect to the inner surface of the duct for providing a peripheral flame sheltered zone between said wall and duct, an annular flange on one end of said wall for securing said diffuser within said duct, a hollow conical diverter coaxially aligned within the diffuser in spaced relation with respect to said wall and centrally disposed within said wall and the duct for providing a central flame sheltered zone, said diverter having its apex in the same vertical plane as the said one end of the wall and facing the large end of said diffuser and the base thereof in the same vertical plane as the small end of the diffuser for diverting the oncoming combustible mixture entering the combustion chamber, a plurality of hollow streamlined conduits and supporting struts fixed to said diffuser and diverter in communication with said peripheral and central sheltered flame zones, and means disposed Within the combustion chamber adjacent and downstream in relation to said sheltered zones for igniting the fuel.

2'. In combination with a ram jet engine, a combustion chamber comprising an annular duct for receiving ram air therethrough, means including a nozzle disposed within said duct to supply fuel to the forward portion of the duct, a hollow frustro-conical diffuser coaxially mounted within the duct downstream from said fuel supply means and having the annular wall thereof converging inwardly in the downstream direction and disposed in spaced relation with respect to the inner surface of the duct for providing an outer annular flame sheltered zone between said wall and duct, an annular flange on one end of said wall in engagement with said duct for securing the diffuser within the duct at the combustion chamber entrance, a hollow conical diverter coaxially aligned with said wall and centrally disposed within the wall and duct in spaced relation with respect to said wall, said diverter being disposed and confined within boundaries ofsaid wall and having its apex facing the large end of said diffuser and the base thereof disposed at the small end of said, diffuser for diverting the oncoming combustible mixture entering the combustion chamber and for providing a central flame sheltered zone adjacent and beyond the base of said diverter, said small end of the diffuser being spaced from said base to provide a ram air mass zone between the outer and central flame sheltered zones, a plurality of streamlined radially disposed conduits and supporting elements secured to said wall and the diverter in fluid communication with the outer and central sheltered zones for supporting the diverter within said diffuser and for providing a plurality of passageways between said zones thereby to facilitate simultaneous ignition and flame propagation as the flame passes through said passageways from the outer zone to the central Zone, and means carried by said duct and disposed within the outer sheltered zone of the combustion chamber for igniting said fuel.

References Cited in the file of this patent UNITED STATES PATENTS 2,592,110 Berggren et al. Apr. 8, 1952 2,656,676 Kallal Oct. 27, 1953 2,657,532 Reid et al. Nov. 3, 1953 2,659,195 Bolanovich Nov. 17, 1953 2,689,457 Kruppe Sept. 21, 1954 2,744,384 Loughran May 8, 1956 

